Geographic Information System (GIS): a computer system designed to allow users
to collect, manage, and analyze large volumes of spatially referenced information and
associated attribute data. The major components of a GIS are the user interface, database
management, data entry, product generation, and spatial data manipulation and analysis.
These functions may be centralized, or distributed across a network.

Global Positioning System (GPS): a navigational tool that allows the user to
determine their location on the surface of the earth (usually within metres), using a
hand-held or aircraft-mounted instrument linked to radio signals from several satellites.

Hazard: the degree to which the characteristics of thesampling entity
(usually a tree or a stand) make it vulnerable to damage. It is equivalent to
susceptibility.

Hawksworth Six-class Rating System: a standardized method of assessing the
severity of dwarf mistletoe infestations on a tree. The method is fully described in the Dwarf
Mistletoe Management Guidebook, Section 5.3.

Incidence: the proportion (01) or percentage (0100%) of damage
agentaffected sampling entities (normally a tree) within a sampling unit (normally a
plot or a stand). To avoid confusion when using incidence, always indicate the sampling
entity and sampling unit in order to ensure clarity. Where the proportion of damaging
agentaffected stands or polygons (sampling entity) is of interest in a higher-level
sampling unit, use occurrence.

Intensity: a general characterization of the total amount of a damage within a
specific population and a function (not necessarily arithmetic) of incidence and severity.

Inventory Type Group (ITG): the designation of species composition by one of 42
type groups, each one being a unique combination of pure or mixed tree species.

Multi-storey: A stand is considered multi-storey if the layers 1 or 2 have a
crown closure >6% and one of these layers is in combination with layer 3 and/or 4. In
order to survey using the multi-storey method, an opening must have at least a minimum of
three layers present or one of the following combinations: layers 1 and 4, layers 2 and 4,
or layers 1 and 3.

Occurrence: the proportion of damage agentaffected stands or polygons
within a higher-level sampling unit (e.g., inventory or growth type groups, or BEC zone
subzones or variants).

Pixel: a type of fixed plot used to estimate prevalence as the percentage area
infected; often only the presence or absence of the damaging agent is recorded for each
pixel.

Population: a collection of sampling entities about which we wish to make an
inference.

Prevalence: the proportion of sampling entities (in a given population of
interest) affected by a particular damaging agent.

Probe (beetle): a systematic strip transect survey through a stand to obtain
detailed information on infestation levels, history, and stand data needed to make
management decisions.

Risk: the probability and expected severity of sampling entity damage. It is a
function of numerous components, including sampling entity, hazard, sampling unit
conditions, proximity to damaging agents, and the incidence of those agents.

Sampling entity: an object on which a measurement is taken (normally a tree or a
stand).

Sampling unit: a non-overlapping collection of sampling entities from a
population.

Severity: the quantity of damage, or the quantity of a damaging agent, affecting
sample entities within a sampling unit. It is a damage-rating measurement, (an average)
that considers only affected entities and is damage type or agent specific. Severity
cannot be applied at the stand level. The terms intensity, yield/growth effects, or
impacts should be applied at the stand or higher levels.

Strip: a sampling unit laid out by measuring an equal distance on either side of
a transect; a special type of fixed plot; other names include strip transect, probe line,
and strip plot.

Susceptibility: term equivalent tohazard.

Walkthrough: an initial reconnaissance of an area; for bark beetles a
non-systematic, low-intensity type of ground survey assessing damage. Used to make initial
assessment of situations and confirm aerial survey information.